/*
 * FileSaver.js
 * A saveAs() FileSaver implementation.
 *
 * By Eli Grey, http://eligrey.com
 *
 * License : https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md (MIT)
 * source  : http://purl.eligrey.com/github/FileSaver.js
 */

// The one and only way of getting global scope in all environments
// https://stackoverflow.com/q/3277182/1008999
var _global = typeof window === 'object' && window.window === window
    ? window : typeof self === 'object' && self.self === self
    ? self : typeof global === 'object' && global.global === global
    ? global
    : this

function bom (blob, opts) {
    if (typeof opts === 'undefined') opts = { autoBom: false }
    else if (typeof opts !== 'object') {
        console.warn('Deprecated: Expected third argument to be a object')
        opts = { autoBom: !opts }
    }

    // prepend BOM for UTF-8 XML and text/* types (including HTML)
    // note: your browser will automatically convert UTF-16 U+FEFF to EF BB BF
    if (opts.autoBom && /^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
        return new Blob([String.fromCharCode(0xFEFF), blob], { type: blob.type })
    }
    return blob
}

function download (url, name, opts) {
    var xhr = new XMLHttpRequest()
    xhr.open('GET', url)
    xhr.responseType = 'blob'
    xhr.onload = function () {
        saveAs(xhr.response, name, opts)
    }
    xhr.onerror = function () {
        console.error('could not download file')
    }
    xhr.send()
}

function corsEnabled (url) {
    var xhr = new XMLHttpRequest()
    // use sync to avoid popup blocker
    xhr.open('HEAD', url, false)
    try {
        xhr.send()
    } catch (e) {}
    return xhr.status >= 200 && xhr.status <= 299
}

// `a.click()` doesn't work for all browsers (#465)
function click (node) {
    try {
        node.dispatchEvent(new MouseEvent('click'))
    } catch (e) {
        var evt = document.createEvent('MouseEvents')
        evt.initMouseEvent('click', true, true, window, 0, 0, 0, 80,
            20, false, false, false, false, 0, null)
        node.dispatchEvent(evt)
    }
}

// Detect WebView inside a native macOS app by ruling out all browsers
// We just need to check for 'Safari' because all other browsers (besides Firefox) include that too
// https://www.whatismybrowser.com/guides/the-latest-user-agent/macos
var isMacOSWebView = _global.navigator && /Macintosh/.test(navigator.userAgent) && /AppleWebKit/.test(navigator.userAgent) && !/Safari/.test(navigator.userAgent)

var saveAs = _global.saveAs || (
        // probably in some web worker
        (typeof window !== 'object' || window !== _global)
            ? function saveAs () { /* noop */ }

            // Use download attribute first if possible (#193 Lumia mobile) unless this is a macOS WebView
            : ('download' in HTMLAnchorElement.prototype && !isMacOSWebView)
            ? function saveAs (blob, name, opts) {
            var URL = _global.URL || _global.webkitURL
            // Namespace is used to prevent conflict w/ Chrome Poper Blocker extension (Issue #561)
            var a = document.createElementNS('http://www.w3.org/1999/xhtml', 'a')
            name = name || blob.name || 'download'

            a.download = name
            a.rel = 'noopener' // tabnabbing

            // TODO: detect chrome extensions & packaged apps
            // a.target = '_blank'

            if (typeof blob === 'string') {
                // Support regular links
                a.href = blob
                if (a.origin !== location.origin) {
                    corsEnabled(a.href)
                        ? download(blob, name, opts)
                        : click(a, a.target = '_blank')
                } else {
                    click(a)
                }
            } else {
                // Support blobs
                a.href = URL.createObjectURL(blob)
                setTimeout(function () { URL.revokeObjectURL(a.href) }, 4E4) // 40s
                setTimeout(function () { click(a) }, 0)
            }
        }

            // Use msSaveOrOpenBlob as a second approach
            : 'msSaveOrOpenBlob' in navigator
            ? function saveAs (blob, name, opts) {
            name = name || blob.name || 'download'

            if (typeof blob === 'string') {
                if (corsEnabled(blob)) {
                    download(blob, name, opts)
                } else {
                    var a = document.createElement('a')
                    a.href = blob
                    a.target = '_blank'
                    setTimeout(function () { click(a) })
                }
            } else {
                navigator.msSaveOrOpenBlob(bom(blob, opts), name)
            }
        }

            // Fallback to using FileReader and a popup
            : function saveAs (blob, name, opts, popup) {
            // Open a popup immediately do go around popup blocker
            // Mostly only available on user interaction and the fileReader is async so...
            popup = popup || open('', '_blank')
            if (popup) {
                popup.document.title =
                    popup.document.body.innerText = 'downloading...'
            }

            if (typeof blob === 'string') return download(blob, name, opts)

            var force = blob.type === 'application/octet-stream'
            var isSafari = /constructor/i.test(_global.HTMLElement) || _global.safari
            var isChromeIOS = /CriOS\/[\d]+/.test(navigator.userAgent)

            if ((isChromeIOS || (force && isSafari) || isMacOSWebView) && typeof FileReader !== 'undefined') {
                // Safari doesn't allow downloading of blob URLs
                var reader = new FileReader()
                reader.onloadend = function () {
                    var url = reader.result
                    url = isChromeIOS ? url : url.replace(/^data:[^;]*;/, 'data:attachment/file;')
                    if (popup) popup.location.href = url
                    else location = url
                    popup = null // reverse-tabnabbing #460
                }
                reader.readAsDataURL(blob)
            } else {
                var URL = _global.URL || _global.webkitURL
                var url = URL.createObjectURL(blob)
                if (popup) popup.location = url
                else location.href = url
                popup = null // reverse-tabnabbing #460
                setTimeout(function () { URL.revokeObjectURL(url) }, 4E4) // 40s
            }
        }
    )

_global.saveAs = saveAs.saveAs = saveAs

if (typeof module !== 'undefined') {
    module.exports = saveAs;
}
